Js. Ebdon et Am. Petrovic, MORPHOLOGICAL AND GROWTH-CHARACTERISTICS OF LOW-WATER AND HIGH-WATER USE KENTUCKY BLUEGRASS CULTIVARS, Crop science, 38(1), 1998, pp. 143-152
As the competition for water increases, there is a need to conserve li
mited water resources applied to irrigated turfgrass sites. Consistent
with this effort is the identification of water conserving Kentucky b
luegrass (Pea pratensis L.) because low consumptive water use may be i
mportant in reducing irrigation requirements by enhancing drought resi
stance. Low evapotranspiration (ET) rates under nonlimiting soil moist
ure conditions have been associated with turfgrass morphology and grow
th characteristics that increase canopy resistance to ET and reduce le
af area components. Much of this previous research emphasized warm-sea
son turfgrass. A greenhouse study was conducted to determine the relat
ionship between morphological and growth characteristics in 61 Kentuck
y bluegrass (KEG) cultivars and comparative water use, By means of clu
ster analysis, the 61 KEG cultivars were categorized as either low-or
high-water use cultivars based on ET rates evaluated in the growth cha
mber across three evaporative demand environments (1.263, 1.664, and 2
.261 kPa VPD). Morphological and growth characteristics were assessed
from unmowed, spaced plants and mowed turfgrass grown in fritted clay
tilled lysimeters. Based on single plant morphology, low-water use cul
tivars had 13% more horizontal leaf orientation, 6% narrower leaf text
ure, 13% more lateral shoots per plant, 12% slower vertical leaf exten
sion rate, 2% more leaves per shoot, and 7% shorter leaf blades and sh
eaths than the high-water use cultivars. Based on turfgrass morphology
from mowed lysimeters, the low-water use cultivars had 17% more horiz
ontal leaf orientation, 10% narrower leaf texture, 15% more shoots, 4%
slower vertical leaf extension rate, and 4% shorter leaf sheaths than
the high-water use group. Canopy resistance to ET was not measured in
this study; however, leaf angle (assumed component of canopy resistan
ce) was the only plant characteristics evaluated under mon ed conditio
ns whose correlation with turfgrass ET exceeded 0.50 in absolute value
. Differences observed among water use groups based on single plant-an
d turfgrass-morphology was not always consistent with the high canopy
resistance to ET/low leaf area hypothesis. However, characteristics we
re identified which may be useful in selecting for KBG with a low-wate
r use pattern.